Photonic integrated circuit to glass substrate alignment through dual cylindrical lens

ABSTRACT

An electronic device comprises a photonic integrated circuit (PIC) including at least one optical signal source, an emitting lens disposed on the PIC to steer light emitted by the at least one optical signal source in a direction substantially parallel to a first surface of the PIC, and an optical element disposed on the PIC and having a curved surface in a shape of a quarter cylinder that is configured to steer light emitted from the emitting lens in a direction substantially orthogonal to the first surface of the PIC.

TECHNICAL FIELD

Embodiments pertain to photonic integrated circuits (PICs). Someembodiments relate to techniques to couple an optical signal from a PICto a waveguide.

BACKGROUND

A photonic integrated circuit (PIC) can generate an optical signal.Optically coupling the optical signal to a waveguide allows the opticalsignal to be used in an optical interface that could be used as ahigh-speed interface between electronic devices. Waveguides could befabricated in glass substrates, but there is not a well-establishedsolution for optically coupling between the PIC and a glass substratehaving a waveguide.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of an example of an electronic device having aphotonic integrated circuit (PIC) in accordance with some embodiments;

FIG. 2 is an illustration of the optical element of an electronic devicein accordance with some embodiments;

FIG. 3 is illustration of an example of an electronic device mounted ona glass substrate in accordance with some embodiments;

FIG. 4 is illustration of another example of an electronic devicemounted on a glass substrate in accordance with some embodiments;

FIG. 5 is an illustration of portions of an example of an electronicdevice having multiple optical channels in accordance with someembodiments;

FIG. 6 is a flow diagram of a method of making an electronic device inaccordance with some embodiments;

FIG. 7 illustrates a system level diagram in accordance with someembodiments.

DETAILED DESCRIPTION

The following description and the drawings sufficiently illustratespecific embodiments to enable those skilled in the art to practicethem. Other embodiments may incorporate structural, logical, electrical,process, and other changes. Portions and features of some embodimentsmay be included in, or substituted for, those of other embodiments.Embodiments set forth in the claims encompass all available equivalentsof those claims.

A glass substrate could potentially be used as a waveguide medium tocarry optical signals in a photonic assembly or to integrate photonicsinto a conventional electronic assembly. However, using glass substrateswith waveguides is not widely adopted, and currently there is nowell-established solution for an optical coupling between a photonicintegrated circuit (PIC) and a waveguide formed using a glass substrate.An optical coupling between the PIC and the waveguide should have lowsignal loss. Optical signal loss can be reduced by having an optimizedalignment between the PIC and the waveguide. But alignment of theoptical coupling between the PIC and the waveguide shouldn't becomplicated. A relatively relaxed tolerance for alignment of the opticalcoupling between the PIC and the waveguide may allow the alignment to bepassive. This would reduce the complexity of assemblies that includephotonic devices.

FIG. 1 is an illustration of an example of an electronic device 102 thatincludes a PIC 104. The PIC 104 includes at least one optical signalsource 106 or other optical signal medium (e.g., a waveguide). Theoptical signal source 106 may be a laser diode. The electronic device102 includes an emitting lens 108 and another optical element 110. Theemitting lens 108 is shown from the side in FIG. 1 . In some examplesthe emitting lens 108 has an arc shape. In some examples, the emittinglens 108 has an orthogonal half-cylinder shape orthogonal to the topsurface of the PIC 104 as can be seen in FIG. 5 . The emitting lens 108may be fabricated with the PIC 104, or the emitting lens 108 may beadded to the PIC 104 after the PIC 104 is fabricated. The emitting lens108 is shown next to the optical signal source 106, but anotherwaveguide may be arranged between the optical signal source 106 and theemitting lens 108.

The emitting lens 108 receives light from the optical signal source andsteers the light toward the optical element 110. The arrows show thatthe emitting lens 108 expands the width of the optical signal from thePIC 104. The arrows also show that the light is sent substantially in adirection parallel to the top surface of the PIC 104 to the opticalelement 110 (e.g., within a few degrees of parallel), although the lightbeam is expanding.

The PIC 104 may include a buried insulator layer 118 (e.g., a buriedoxide or BOX layer) at a height intermediate the top surface of the PIC104 and the bottom surface of the PIC 104. The optical structures of thePIC 104 may be fabricated against the buried insulator layer 118. Theemitting lens 108 is arranged on the PIC above the buried oxide layer118.

The optical element 110 includes a support portion 114 and a curvedportion 112. The curved portion 112 may be another lens or lens portionof the optical element. In some examples, the curved surface of thecurved portion 112 includes a mirror. The optical element 110 is acollimating element that (as shown by the arrows) sends a collimatedlight beam vertically away from the top surface of the PIC 104 andsubstantially orthogonal to the top surface. Thus, the curved surfaceprovides a one-dimensional total internal reflection (1D TIR) off-axiscollimating optical element.

The support portion 114 of the optical element has a surface facing theemitting lens that is perpendicular to the top surface of the PIC 104.There may be a space 116 between the emitting lens and the opticalelement 110. Space 116 may be an air space. In some examples, space 116is filled with an epoxy that has a low refractive index. Thesubstantially perpendicular surface of the support portion 114 faces theemitting lens 108 and receives light from emitting lens 108, and thelight passes through the support portion 114 to the curved surface. Theoptical element 110 may be fabricated as a single piece to avoidreflections at the interface between the support portion 114 and thecurved portion 112. In certain embodiments, the optical element 110 isfabricated as two pieces and an anti-reflection coating is applied atthe interface between the support portion 114 and the curved portion112.

FIG. 2 is an illustration of the optical element 110 of the electronicdevice 102 of FIG. 1 . The curved portion 112 has a curved surfacesubstantially in a shape of a quarter of a cylinder as though thecylinder was divided into quarters along its axis. In some examples, thecurved surface of the curved portion 112 has a hyperbolic shape. Thesupport portion 114 has a shape like a very wide “T.” The supportportion 114 includes an insertion portion 124 and a stop portion 126.

Returning to FIG. 1 , the PIC 104 includes a second surface 128 lowerthan the top surface 130. The substrate of the PIC 104 includes a recessor cavity open from the second surface 128. The insertion portion of 124of the optical element 110 is inserted into the recess and the stopportion 126 of the optical element 110 is supported by the secondsurface 128 of the substrate. The stop portion 126 rests on thesubstrate and the height of the resting ledge of the support portion 114can be used to set the height of the position of the optical element110.

The optical element 110 can be made from a material transparent toinfrared. Because silicon is transparent to near infrared the opticalelement could include silicon. The support portion 114 could be formedusing crystallographic etching of silicon. The curved portion 112 couldbe formed using greyscale lithography to form the curved surfacefollowed by crystallographic etching to etch through the wafervertically.

FIG. 3 is illustration of an example of the electronic device 102 ofFIG. 1 mounted on a glass substrate 140. The PIC 104 is shown flip-chipmounted on the glass substrate 140 with the optical element 110 facingthe glass substrate. The PIC 104 has bonding pads 120 that are bonded tothe glass substrate using solder bumps 122 (shown as solder balls). Theheight of the solder bumps may be chosen to provide clearance betweenthe optical element 110 and the glass substrate 140. Because theelectronic device 102 is inverted from FIG. 1 , the collimated lightbeam is sent vertically down toward the glass substrate 140.

The glass substrate 140 includes a waveguide 142 and another opticalelement to steer or focus the light received from the electronic device102 onto the waveguide 142. The waveguide 142 may be a single modewaveguide. The waveguide 142 may then transmit the optical signals toanother device in a direction parallel to the top surface of the glasssubstrate 140. The electronic device 102 and the glass substrate 140form an interface to optically connect the optical signal source 106 andthe waveguide 142. The optical element of the glass substrate can be abeam reduction structure to reduce the beam to the mode size of thewaveguide. In FIG. 3 , the optical element of the glass substrate 140includes lens 146 to reduce the beam and a mirror 144 to steer the beaminto the waveguide 142. In certain examples, the lens 146 is a gradientindex (GRIN) lens.

FIG. 4 is illustration of another example of the electronic device 102of FIG. 1 mounted on a glass substrate 140. The difference from theexample of FIG. 2 is in the optical element included in the glasssubstrate 140. In FIG. 4 , the glass substrate 140 includes a curvedmirror 444 to catch the collimated beam from the electronic device 102and focus the beam onto the waveguide 142. The mirrors 144, 444 in FIGS.3 and 4 may be formed by etching a cavity or surface in the glasssubstrate 140 and forming a reflective surface on the etched structure.

In the examples of FIGS. 3 and 4 , one optical signal source andwaveguide pair may be an optical channel that sends optical signals. ThePIC 104 may include multiple optical signal sources and the opticalelement 110 of the electronic device 102 may reflect and collimatemultiple beams for more than one optical channel.

FIG. 5 is an illustration of portions of an example of an electronicdevice 502 having multiple optical channels. The example of FIG. 5 showsthree optical channels, but the electronic device may have anothernumber of optical channels (e.g., 2 channels, 4 channels, 8 channels,etc.).

The electronic device 502 includes a PIC 504, and each optical channelincludes a waveguide 506 of the PIC 504. The electronic device 502includes an emitting lens 508 for each waveguide 506. The emittinglenses 508 have an orthogonal half-cylinder shape. In some examples, theemitting lenses have the shape of a small arc of an orthogonal cylinder.The emitting lenses 508 can be created directly on the PIC 504 using alithography etching process.

Each emitting lens steers light emitted by the corresponding opticalsignal source in a direction substantially parallel to the top surfaceof the PIC 504. The optical signals are expanded to a larger mode torelax the alignment tolerance. The electronic device includes oneoptical element 110 having a curved surface. The curved surface of theoptical element 110 steers light from all the emitting lenses in adirection substantially orthogonal to the surface of the PIC 504 to sendthree collimated light beams vertically from the electronic device—onefor each optical channel.

The PIC 504 is flip chip mounted on a glass substrate (not shown) andthe glass substrate includes a waveguide for each optical channel (threein the example of FIG. 5 ) to receive one of the collimated beams fromthe electronic device 502. The glass substrate includes additionaloptical elements for each optical channel to reduce the mode of acorresponding collimated light beam to the mode of the waveguide andsteer the reduced beam onto the respective waveguide. For instance, theglass substrate may include a lens 144 and mirror 146 as shown in FIG. 3for each waveguide, or the glass substrate may include a curved mirror444 as shown in FIG. 4 for each waveguide.

FIG. 6 is a flow diagram of a method 600 of manufacture of an electronicdevice. The electronic device may be any of the electronic devices ofshown in FIGS. 1 and 3-5 . At block 605, a PIC is formed that includesat least one optical signal source. The optical signal source mayproduce light in the infrared spectrum. The PIC may include a substrateportion and an active portion that includes one or both of activephotonic circuit and active electronic circuits. The active portion maybe formed to include multiple surfaces.

At block 610, an emitting lens is arranged on the PIC. The emitting lensmay be arranged on a second surface below the top surface of the PIC. Insome examples, the second surface is the surface of a buried insulatorlayer of the PIC. The emitting lens may be etched onto the PIC duringforming of the PIC and include silicon (e.g., silicon nitride). Incertain examples, the emitting lens may be separate from the PIC andattached to the PIC. The emitting lens may have a half-disk shape asshown in FIG. 5 . The emitting lens is positioned to steer light emittedby the optical signal source in a direction substantially parallel tothe top surface and the second surface of the PIC.

At block 615, an optical element is attached to the PIC. The opticalelement has a curved surface as shown in the example of FIG. 2 . Thecurved surface steers light received from the emitting lens in adirection substantially orthogonal to the top surface of the PIC.Attaching the optical element may include forming a recess or cavity inthe second surface, and positioning a support portion of the opticalinto the recess with the curved portion on the opposite of the supportportion from the emitting lens so that light received from the emittinglens passes through the support portion to a curved portion of theoptical element. The supporting portion may be fused or glued to thePIC.

The PIC with the attached optical element is mounted on a glasssubstrate. The PIC may include pads (e.g., bonding pads or I/O pads) onthe top surface and mounting the PIC may include disposing solder bumpson the bonding pads and attaching the first surface of the PIC to aglass substrate using the solder bumps. The glass substrate includes awaveguide and another optical element to steer light onto the waveguide.The optical element of the PIC is positioned to provide a collimatedlight beam to the optical element of the glass substrate to steer anoptical signal onto the waveguide. Some examples of the optical elementof the glass substrate include the lens 144 and mirror 146 in theexample of FIG. 3 , and the curved mirror 444 shown in the example ofFIG. 4 . As described regarding FIG. 5 , the PIC and glass substrate mayinclude multiple optical signal sources and waveguides included inmultiple optical channels.

The electronic device and the glass substrate may be included in anoptical interface between two or more higher level devices. Because thelight from the optical signal source is expanded and then refocused, thetolerance needed in the alignment is relaxed, and the aligning andassembly process of the PIC and the waveguide is simplified. An exampleof a higher level electronic device using assemblies with opticalelements as described in the present disclosure is included to show anexample of a higher level device application.

FIG. 7 illustrates a system level diagram, according to one embodimentof the invention. For instance, FIG. 7 depicts an example of anelectronic device (e.g., system) that can include one or more of theoptical interfaces as described in the present disclosure. In oneembodiment, system 700 includes, but is not limited to, a desktopcomputer, a laptop computer, a netbook, a tablet, a notebook computer, apersonal digital assistant (PDA), a server, a workstation, a cellulartelephone, a mobile computing device, a smart phone, an Internetappliance or any other type of computing device. In some embodiments,system 700 is a system on a chip (SOC) system. In one example, two ormore systems as shown in FIG. 7 may be coupled together using one ormore glass interposers as described in the present disclosure.

In one embodiment, processor 710 has one or more processing cores 712and 712N, where N is a positive integer and 712N represents the Nthprocessor core inside processor 710. In one embodiment, system 700includes multiple processors including 710 and 705, where processor 705has logic similar or identical to the logic of processor 710. In someembodiments, processing core 712 includes, but is not limited to,pre-fetch logic to fetch instructions, decode logic to decode theinstructions, execution logic to execute instructions and the like. Insome embodiments, processor 710 has a cache memory 716 to cacheinstructions and/or data for system 700. Cache memory 716 may beorganized into a hierarchal structure including one or more levels ofcache memory.

In some embodiments, processor 710 includes a memory controller 714,which is operable to perform functions that enable the processor 710 toaccess and communicate with memory 730 that includes a volatile memory732 and/or a non-volatile memory 734. In some embodiments, processor 710is coupled with memory 730 and chipset 720. Processor 710 may also becoupled to a wireless antenna 778 to communicate with any deviceconfigured to transmit and/or receive wireless signals. In oneembodiment, the wireless antenna interface 778 operates in accordancewith, but is not limited to, the IEEE 802.11 standard and its relatedfamily, Home Plug AV (HPAV), Ultra-Wide Band (UWB), Bluetooth, WiMax, orany form of wireless communication protocol.

In some embodiments, volatile memory 732 includes, but is not limitedto, Synchronous Dynamic Random Access Memory (SDRAM), Dynamic RandomAccess Memory (DRAM), RAMBUS Dynamic Random Access Memory (RDRAM),and/or any other type of random access memory device. Non-volatilememory 734 includes, but is not limited to, flash memory, phase changememory (PCM), read-only memory (ROM), electrically erasable programmableread-only memory (EEPROM), or any other type of non-volatile memorydevice.

Memory 730 stores information and instructions to be executed byprocessor 710. In one embodiment, memory 730 may also store temporaryvariables or other intermediate information while processor 710 isexecuting instructions. In the illustrated embodiment, chipset 720connects with processor 710 via Point-to-Point (PtP or P-P) interfaces717 and 722. The interfaces 717 and 722 may include one or more opticalinterfaces. Chipset 720 enables processor 710 to connect to otherelements in system 700. In some embodiments of the invention, interfaces717 and 722 operate in accordance with a PtP communication protocol suchas the Intel® QuickPath Interconnect (QPI) or the like. In otherembodiments, a different interconnect may be used.

In some embodiments, chipset 720 is operable to communicate withprocessor 710, 705N, display device 740, and other devices 772, 776,774, 760, 762, 764, 766, 777, etc. Buses 750 and 755 may beinterconnected together via a bus bridge 772. Chipset 720 connects toone or more buses 750 and 755 that interconnect various elements 774,760, 762, 764, and 766. Chipset 720 may also be coupled to a wirelessantenna 778 to communicate with any device configured to transmit and/orreceive wireless signals. Chipset 720 connects to display device 740 viainterface (I/F) 726. Display 740 may be, for example, a liquid crystaldisplay (LCD), a plasma display, cathode ray tube (CRT) display, or anyother form of visual display device. In some embodiments of theinvention, processor 710 and chipset 720 are merged into a single SOC.In one embodiment, chipset 720 couples with (e.g., via interface 724) anon-volatile memory 760, a mass storage medium 762, a keyboard/mouse764, and a network interface 766 via I/F 724 and/or I/F 726, I/O devices774, smart TV 776, consumer electronics 777 (e.g., PDA, Smart Phone,Tablet, etc.). One or more of interfaces 724 and 726 may be an opticalinterface.

In one embodiment, mass storage medium 762 includes, but is not limitedto, a solid state drive, a hard disk drive, a universal serial bus flashmemory drive, or any other form of computer data storage medium. In oneembodiment, network interface 766 is implemented by any type ofwell-known network interface standard including, but not limited to, anEthernet interface, a universal serial bus (USB) interface, a PeripheralComponent Interconnect (PCI) Express interface, a wireless interfaceand/or any other suitable type of interface. In one embodiment, thewireless interface operates in accordance with, but is not limited to,the IEEE 802.11 standard and its related family, Home Plug AV (HPAV),Ultra-Wide Band (UWB), Bluetooth, WiMax, or any form of wirelesscommunication protocol.

While the modules shown in FIG. 7 are depicted as separate blocks withinthe system 700, the functions performed by some of these blocks may beintegrated within a single semiconductor circuit or may be implementedusing two or more separate integrated circuits. For example, althoughcache memory 716 is depicted as a separate block within processor 710,cache memory 716 (or selected aspects of 716) can be incorporated intoprocessor core 712.

The devices, systems, and methods described can provide improved routingof interconnection between ICs for a multichip package in addition toproviding improved transistor density in the IC die. Examples describedherein include two or three IC dies for simplicity, but one skilled inthe art would recognize upon reading this description that the examplescan include more than three IC dice.

Additional Description and Examples

Example 1 includes subject matter (such as an electronic device)comprising a photonic integrated circuit (PIC) including at least onewaveguide, an emitting lens disposed on the PIC to steer light emittedby the at least one waveguide in a direction substantially parallel to afirst surface of the PIC, and an optical element disposed on the PIC andhaving a curved surface in a shape of a quarter cylinder that isconfigured to steer light emitted from the emitting lens in a directionsubstantially orthogonal to the first surface of the PIC.

In Example 2, the subject matter of Example 1, optionally includes thecurved surface of the optical element having a mirror surface.

In Example 3, the subject matter of one or both of Examples 1 and 2optionally includes an optical element that includes a lens including asupport portion and a curved portion. The curved portion includes thecurved surface and the support portion passes the emitted light from theemitting lens to the curved surface.

In Example 4, the subject matter of Example 3 optionally includes a PICthat includes a supporting substrate having a second surfaceintermediate to the first surface of the PIC and a bottom surface of thePIC opposite to the first surface, and a recess in the second surface.The support portion optionally includes an insertion portion and a stopportion, wherein the insertion portion is arranged in the recess and thestop portion is supported by the second surface.

In Example 5, the subject matter of one or any combination of Examples1-4 optionally includes a space between the emitting lens and theoptical element. The optical element includes a perpendicular surfaceperpendicular to the first surface of the PIC, and the optical elementreceives the emitted light from the emitting lens at the perpendicularsurface.

In Example 6, the subject matter of Example 5 optionally includes aburied insulator layer positioned at a height intermediate to the firstsurface of the PIC and a bottom surface opposing the first surface ofthe PIC, and an emitting lens arranged between the first surface and theburied insulator layer.

In Example 7, the subject matter of one or any combination of Examples1-6 optionally includes the first surface including bonding pads.

In Example 8, the subject matter of one or any combination of Examples1-7 optionally includes multiple emitting lenses, a PIC that includesmultiple optical signal sources to each provide an optical signal to arespective emitting lens of the multiple emitting lenses, and the curvedsurface of the optical element is configured to steer light emitted fromthe emitting lenses in a direction substantially orthogonal to the firstsurface of the PIC.

Example 9 includes subject matter (such as a method of forming anelectronic device) or can optionally be combined with one or anycombination of Examples 1-8 to include such subject matter, comprisingforming a photonic integrated circuit (PIC) that includes at least oneoptical signal source, arranging an emitting lens on the PIC, theemitting lens positioned to steer light emitted by the optical signalsource in a direction substantially parallel to a first surface of thePIC, and attaching an optical element on the PIC, the optical elementhaving a curved surface in a shape of a quarter cylinder, wherein thecurved surface is configured to steer light received from the emittinglens in a direction substantially orthogonal to the first surface of thePIC.

In Example 10, the subject matter of Example 9 optionally includesforming a second surface intermediate to the first surface of the PICand a bottom surface of the PIC, forming a recess in the second surface,and positioning a support portion of the optical element in the recess.

In Example 11, the subject matter of Example 10 optionally includesarranging the emitting lens on the second surface of the PIC, andpositioning the support portion of the optical element so that lightreceived from the emitting lens passes through the support portion to acurved portion of the optical element.

In Example 12, the subject matter of one or both of Examples 10 and 11optionally includes forming a buried insulator layer of the PIC, and thesecond surface is a surface of the buried insulator layer.

In Example 13, the subject matter of one or any combination of Examples10-12 optionally includes disposing solder bumps on bonding pads on thefirst surface of the PIC, and attaching the first surface of the PIC toa glass substrate using the solder bumps, wherein the glass substrateincludes a waveguide.

In Example 14, the subject matter of one or any combination of Examples9-12 optionally includes arranging an emitting lens for each of multipleoptical signal sources of the PIC, and a curved surface of the opticalelement configured to steer light received from the multiple emittinglens in a direction substantially orthogonal to the first surface of thePIC. The method further includes attaching the first surface of the PICto a glass substrate having a waveguide for each of the multiple opticalsignal sources.

In Example 15, the subject matter of one or any combination of Examples9-14 optionally includes attaching the first surface of the PIC to aglass substrate that includes a waveguide. The glass substrateoptionally includes a curved mirror configured to focus the lightreceived from the optical element onto the waveguide.

In Example 16, the subject matter of one or any combination of Examples9-15 optionally includes attaching the first surface of the PIC to aglass substrate that includes a waveguide. The glass substrate includinga mirror configured to steer the light received from the optical elementonto the waveguide and a lens configured to focus the light receivedfrom the optical element onto the mirror.

Example 17 includes subject matter (such as an electronic device) or canoptionally by combined with one or any combination of Examples 1-6 toinclude such subject matter, comprising a photonic integrated circuit(PIC) mounted on a glass substrate. The PIC includes at least oneoptical signal source, at least one emitting lens positioned to steerlight emitted by the at least one optical signal source in a directionsubstantially parallel to a first surface of the PIC, and a firstoptical element having a curved surface in a shape of a quarter cylinderthat is configured to steer light emitted from the at least one emittinglens in a direction substantially orthogonal to the first surface of thePIC and wherein the first surface of the PIC is attached to the topsurface of the glass substrate. The glass substrate a second opticalelement configured to receive light from the PIC perpendicular to a topsurface of the glass substrate and focus the received light on at leastone waveguide that extends within the glass substrate in a directionparallel to the top surface of the glass substrate.

In Example 18, the subject matter of Example 17 optionally includes thesecond optical element being a curved mirror configured to steer thelight received from the PIC onto the wave guide.

In Example 19, the subject matter of Example 17 optionally includes asecond optical element including a lens on the glass substrate to reducelight received from the first optical element and a mirror configured tosteer the light onto the waveguide.

In Example 20, the subject matter of one or any combination of Examples17-19 optionally includes multiple optical signal sources, an emittinglens for each optical signal source, an optical element having a curvedsurface configured to steer light emitted from the emitting lenses in adirection substantially orthogonal to the first surface of the PIC tothe top surface of the glass substrate, and a glass substrate thatincludes a waveguide for each optical signal source.

These non-limiting examples can be combined in any permutation orcombination. The Abstract is provided to allow the reader to ascertainthe nature and gist of the technical disclosure. It is submitted withthe understanding that it will not be used to limit or interpret thescope or meaning of the claims. The following claims are herebyincorporated into the detailed description, with each claim standing onits own as a separate embodiment.

What is claimed is:
 1. An electronic device comprising: a photonicintegrated circuit (PIC) including at least one waveguide; an emittinglens disposed on the PIC to emit light from the at least one waveguidein a direction substantially parallel to a first surface of the PIC; andan optical element disposed on the PIC and having a curved surface in ashape of a quarter cylinder that is configured to steer light emittedfrom the emitting lens in a direction substantially orthogonal to thefirst surface of the PIC.
 2. The electronic device of claim 1, whereinthe curved surface of the optical element includes a mirror surface. 3.The electronic device of claim 1: wherein the optical element includes alens including a support portion and a curved portion; and wherein thecurved portion includes the curved surface and the support portionpasses the emitted light from the emitting lens to the curved surface.4. The electronic device of claim 3, wherein the PIC includes asupporting substrate having a second surface intermediate to the firstsurface of the PIC and a bottom surface of the PIC opposite to the firstsurface, and a recess in the second surface; and wherein the supportportion includes an insertion portion and a stop portion, wherein theinsertion portion is arranged in the recess and the stop portion issupported by the second surface.
 5. The electronic device of claim 1,including: a space between the emitting lens and the optical element;and wherein the optical element includes a perpendicular surfaceperpendicular to the first surface of the PIC, and the optical elementreceives the emitted light from the emitting lens at the perpendicularsurface.
 6. The electronic device of claim 5, including: a buriedinsulator layer positioned at a height intermediate to the first surfaceof the PIC and a bottom surface opposing the first surface of the PIC;and wherein the emitting lens is arranged between the first surface andthe buried insulator layer.
 7. The electronic device of claim 1, whereinthe first surface includes bonding pads.
 8. The electronic device ofclaim 1, including: multiple emitting lenses; wherein the PIC includesmultiple optical signal sources to each provide an optical signal to arespective emitting lens of the multiple emitting lenses; and whereinthe curved surface of the optical element is configured to steer lightemitted from the emitting lenses in a direction substantially orthogonalto the first surface of the PIC.
 9. A method of forming an electronicdevice, the method comprising: forming a photonic integrated circuit(PIC) that includes at least one waveguide; arranging an emitting lenson the PIC, the emitting lens positioned to steer light emitted by thewaveguide in a direction substantially parallel to a first surface ofthe PIC; and attaching an optical element on the PIC, the opticalelement having a curved surface in a shape of a quarter cylinder,wherein the curved surface is configured to steer light received fromthe emitting lens in a direction substantially orthogonal to the firstsurface of the PIC.
 10. The method of claim 9, wherein the forming thePIC includes: forming a second surface intermediate to the first surfaceof the PIC and a bottom surface of the PIC; forming a recess in thesecond surface; and wherein the attaching the optical element includespositioning a support portion of the optical element in the recess. 11.The method of claim 10, wherein the arranging the emitting lens includesarranging the emitting lens on the second surface of the PIC; andwherein the attaching the optical element includes positioning thesupport portion of the optical element so that light received from theemitting lens passes through the support portion to a curved portion ofthe optical element.
 12. The method of claim 10, wherein the forming thePIC includes forming a buried insulator layer of the PIC, and the secondsurface is a surface of the buried insulator layer.
 13. The method ofclaim 10, including: disposing solder bumps on bonding pads on the firstsurface of the PIC; and attaching the first surface of the PIC to aglass substrate using the solder bumps, wherein the glass substrateincludes a waveguide.
 14. The method of claim 9, wherein the arrangingan emitting lens on the PIC includes arranging an emitting lens for eachof multiple optical signal sources of the PIC, and the curved surface ofthe optical element is configured to steer light received from themultiple emitting lens in a direction substantially orthogonal to thefirst surface of the PIC; and wherein the method further includesattaching the first surface of the PIC to a glass substrate having awaveguide for each of the multiple optical signal sources.
 15. Themethod of claim 9, including attaching the first surface of the PIC to aglass substrate that includes a waveguide, wherein the glass substrateincludes a curved mirror configured to focus the light received from theoptical element onto the waveguide.
 16. The method of claim 9, includingattaching the first surface of the PIC to a glass substrate thatincludes a waveguide, wherein the glass substrate includes: a mirrorconfigured to steer the light received from the optical element onto thewaveguide; and a lens configured to focus the light received from theoptical element onto the mirror.
 17. An electronic device comprising: aphotonic integrated circuit (PIC) mounted on a glass substrate; whereinthe PIC includes: at least one optical signal source; at least oneemitting lens positioned to steer light emitted by the at least oneoptical signal source in a direction substantially parallel to a firstsurface of the PIC; and a first optical element having a curved surfacein a shape of a quarter cylinder that is configured to steer lightemitted from the at least one emitting lens in a direction substantiallyorthogonal to the first surface of the PIC and wherein the first surfaceof the PIC is attached to the top surface of the glass substrate; andwherein the glass substrate includes: a second optical elementconfigured to receive light from the PIC perpendicular to a top surfaceof the glass substrate and focus the received light on at least onewaveguide that extends within the glass substrate in a directionparallel to the top surface of the glass substrate.
 18. The electronicdevice of claim 17, wherein the second optical element is a curvedmirror configured to steer the light received from the PIC onto the waveguide.
 19. The electronic device of claim 17, wherein the second opticalelement includes a lens on the glass substrate to reduce light receivedfrom the first optical element and a mirror configured to steer thelight onto the waveguide.
 20. The electronic device of claim 17, whereinthe at least one optical signal source includes multiple optical signalsources; wherein the at least one emitting lens includes an emittinglens for each optical signal source; wherein the curved surface of theoptical element is configured to steer light emitted from the emittinglenses in a direction substantially orthogonal to the first surface ofthe PIC to the top surface of the glass substrate; and wherein the glasssubstrate includes a waveguide for each optical signal source.